There is proposed a system which verifies alteration of an image file generated by an image sensing apparatus such as a digital camera (see, e.g., U.S. Pat. No. 5,499,294 and Japanese Patent Application Laid-Open No. 2002-244924). In such system, when an image file containing image data and accessory information (thumbnail image, photographing date & time, shutter speed, F-number, ISO sensitivity, model name, manufacturing number, and the like) is determined to have been altered, the accessory information may have been altered.
However, the conventional system does not consider notification of accessory information which may have been altered to the user in an easy-to-understand way.